Blood pressure cuff with calibrated holding means

ABSTRACT

A blood pressure cuff including a visual indication of the limit of assured accuracy in the blood pressure recording. The point of the cuff closure is marked to show said limit, the indicia being located in reference to the ratio which the diameter of the limb encircled by the cuff bears to the width of the occluding bladder. The markings assure acceptance (despite differences of opinion in the scientific community) by the major recognized associations concerned with the establishment of cuff design standards. The cuff minimizes disregard of the indicia and the consequent taking of an inaccurate recording, by incorporation of a &#39;&#39;&#39;&#39;failsafe&#39;&#39;&#39;&#39; connection between the mating cuff ends. The connecting means loses holding power and fails to maintain closure of the cuff when gas pressure is applied to the bladder in the normal fashion, if the ratio of limb diameter to bladder width exceeds known standards.

United States Patent 1 3,699,945 Hanafin [451 Oct. 24, 1972 [54] BLOODPRESSURE CUFF WITH {57] ABSTRACT CALIBRATED HOLDING MEANS [72] Inventor:Paul M. Hanafin, 240 Readington Road, Somerville, NJ. 08876 [22] Filed:July 30, 1970 [21] Appl. No.: 59,620

[ 52] U.S. Cl. ..128/2.05 C, 128/327 [51] Int. Cl. ..A61b 5/02 [58]Field of Search ..l28/2.05 A, 2.05 C, 2.05 G,

128/205 M, 2.05 O, 2.05 R, 2.05 V, 327' [56] References Cited UNITEDSTATES PATENTS 3,279,459 10/1966 Shenker l28/2.05 C 3,467,077 9/1969Cohen ..l28/2.05 C 1,930,459 10/1933 Bandoly ..128/2.05 G 3,153,41410/1964 Beall et al ..l28/327 Primary Examine rWi1liam E. KammAttorney-Sperry and Zoda A blood pressure cuff including a visualindication of the limit of assured accuracy in the blood pressurerecording. The point of the cuff closure is marked to show said limit,the indicia being located in reference to the ratio which the diameterof the limb encircled by the cuff bears to the width of the occludingbladder. The markings assure acceptance (despite differences of opinionin the scientific community) by the major recognized associationsconcerned with the establishment of cuff design standards.

The cuff minimizes disregard of the indicia and the consequent taking ofan inaccurate recording, by incorporation of a fail-safe connectionbetween the mating cuff ends. The connecting means loses holding powerand fails to maintain closure of the cuff when gas pressure is appliedto the bladder in the normal fashion, if the ratio of limb diameter tobladder width exceeds known standards.

10 Claims, 8 Drawing Figures PATENTEU 0m 24 I972 l nllllllrlirl'liuillllllllllli PAUL M. Hnun s'nv RTTOEHEVS moon PRESSURE CUFF warnCALIBRATED HOLDING wmANs BACKGROUND OF THE INVENTION cerned with theprovision of an improved blood pressure cuff to be utilized as a part ofa diagnostic device or instrument.

The invention is primarily concerned with embodying, in a blood pressurecuff, a means of marking thereon a limit of assured accuracy, using as apoint of reference the ratio of limb diameter to occluding bladderwidth. Further incorporated in the invention is a fail-safe feature,such that a disregard of the indicia of the limit of assured accuracy,whether intentional or inadvertent, will produce a loss of holding powerin the cuff with resultant opening thereof as soon maximum gas pressureis applied in the normal method employed in blood pressuredetermination.

2. Description of the Prior Art The prior art indicates a recognition ofthe criticality of occluding bladder width, and suggestion has been madethat there be certain ratios of bladder width to limb diameter. And,there has also been discussion along with efforts to achievestandardization, with respect to the extent to which the bladder shouldencircle the limb, in order to assure as much as possible the taking ofan accurate recording.

Von Rechlinghausen, in 1901 suggested that the width of the occludingcuff was of critical importance since a cuff too narrow gave generallyhigh blood pressure values. His recommendations that a minimum bladderwidth of 12 cm. on the adult upper arm have been carried forward to thepresent time. Hill and McQueen in 1916 tended to explain the widthrequirement as necessary for occlusion of venous outlets.

Medical standards entitled: Standardization of blood pressure readingswere promulgated by the American Heart Association, Inc. in 1939, basedon the joint recommendations of the American Heart Association and theCardiac Society of Great Britain and Ireland. These were the firstuniversally accepted domestic standards on cuff sizing. Bladderspecifications set forth in these standards resulted in a 12 or 13 cm.width and a 23-24 cm. length on the adult cuff. The requirement of a 50percent bladder encirclement of the arm was noted and the suggestion tocenter the bladder over the artery to be measured was made.

In 1951, and again in 1967, these recommendations were rewritten by theAmerican Heart Association in a document entitled: Recommendation forHuman Blood Pressure Determination by Sphymomanometer. Bladderrequirements were changed to include a provision that the inflation bagshould, roughly speaking, be percent wider than the diameter of the armor thigh on which it is to be used. Specific widths for other than adultsize cuffs were given. A 50 percent bladder limb encirclement was statedas desirable and the notation was made that some authorities believethat any risk of misapplication should be obviated by use of a bag thatnearly or completely encircles the limb.

It should be noted that research articles on blood pressure universallyinclude the 1939, 1951 and 1967 recommendations as standard. Despite the1951 and 1967 recommendations on the importance of cufi widths, however,no one has to my knowledge provided a cuif which indicates therecommended ratio or in any way indicates conformance to ratiorecommendations. The closest approach to ratio is conformance based onan article at Edinburgh University, Scotland which attempted to assignplus or minus values for various size arms. A cuff conforming to thesespecifications was advertised and marketed in England in the late 1950s.Current literature, since 1960, does not support a numerical value basedon arm size with adult cuffs and .the

scientific reason for variations due to cuff width-arm diameter ratiosis open to many interpretations. Further, a suggestion on a fail-saferatio has been lacking in the literature.

There is also a body of clinical and scientific medical evidence to theeffect that if a bladder completely or nearly encircles a limb with awidth of 15, 14 or 12 cm. (depending on the author) the trueinterarterial pressure is most nearly approximated by the indirect blood5 pressure recording method.

Karvonen in 1953 and the World Health Organization recommendations tookthis position. However, it is interesting to note that Europeanauthorities and manufacturers have tended to reduce bladder length from35 to 40 cm. toward the historic British and American standards of 23cm. length. Recently Simpson in 1965 and King in 1966 have attempted toprove the validity of longer length of bladder with nearly' completeencirclement.

The studies of Moss in 1962 did much to improve accuracy in child cuffsizing in the ranges of infant, child and newborn cuff sizes. Hisconclusion was that cuff width to arm diameter was of prime importanceover other factors. However, his recommendations resulted in cuffs ineach size which nearly encircled the limb within fixed bladder widthsand conformed to the American Heart Association ratio recommendations.

It will thus be seen that different views are held by scientificauthorities, with respect to the ratio which cuff width should bear tolimb diameter, and with respect to the extent of limb encirclement bythe occluding bladder. It is well settled, however, that in point ofactual fact the width of the bladder is significant, the extent ofencirclement is significant also, and the ratio of the width of the cuffto the diameter of the encircled limb is, indeed, also of significantand undoubtedly even critical importance.

Yet, to my knowledge, no cuff has been designed so far that will assurethe taking of an accurate recording if visual indicia thereupon arerespected by the user, and which will further assure failure to maintaincuff closure if the user goes beyond any limits recognized by competentscientific authority, even though said authority may differ from otherschools of thought bearing upon the subject.

SUMMARY OF THE INVENTION Summarized briefly, the invention comprises ablood pressure cuff which, in the first place, can be made in any ofcertain main sizes, such as, for example, adult, child, and obese. Ineach of these main categories, the

cuff incorporates the conventional inflation bladder, means forconnection of the bladder to a source of air under pressure, and meansfor associating the same with a conventional sphygmomanometer. Theinvention resides in the provision of indicia indicating (whether thecuff be of theadult, obese or child size) whether or not the appliedcuff is within limits of assured accuracy as determined by recognizedbodies of scientific opinion.

The invention further incorporates a fail-safe connection between theoverlapping end portions of the applied cuff, such that the connectionmeans will fail upon application of air pressure, if its use isattempted beyond a predetermined tolerance value as regards the ratio ofarm diameter to cuff width.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is an elevational view of anopened blood pressure cuff according to the present invention;

FIG. 2 is an elevational view of the cuff, showing the other facethereof;

FIG. 3 is a perspective view, showing the cuff during its application toan arm;

FIG. 4 is a transverse sectional view substantially on line 4-4 of FIG.1;

FIG. 5 is a transverse sectional view substantially on line 5-5 of FIG.2;

FIG 6 is a somewhat diagramatic edge view of the cuff, as it appearswhen properly applied and within safe limits;

FIG. 7 is a view like FIG. 6, showing the cuff applied under conditionsexceeding the reasonable excess value above recommended limits, thedotted lines DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIGS.1 and 2, the illustratedcuff 10 comprises a length of fabric 12 foldedupon itself along a transverse fold line 14, which thus defines one endof the cuff. A line of stitching 16 extends along the longitudinal edgesand the registered ends of the material, whereby the cuff comprises anelongated, rectangular body of double thickness adapted to be wrappedabout the patients arm A.

A transverse line of stitching 18 is extended between theoppositelongitudinal edges of the body 19 defined by the superimposed portionsof the fabric, and defines, between the line of stitching 18 and the endof the body more remote therefrom, a hollow, rectangular space which isor accepts an occluding bladder 20.

It will be noted at this point that the term occluding bladder as usedherein is so used in the broad sense. Quite possibly, in some bloodpressure cuffs constructed according to the present invention, thebladder 20 might itself receive an inflation bag, not shown in thepresent drawings. Or, in other forms, the bladder 20 might itself beinflated. It is sufficient to note for the purposes of the presentapplication that the term bladder as used in the description and claimsof this application is intended to refer to a portion of the cuff whichmay itself, or by the provision of an insertable bag, be connectable toa source of air under pressure for the purpose of inflating the sameduring the normal use of the device.

At the opposite side of the line of stitching 18, that is, the portionof the device lying between said line of stitching and fold line 14, thecuff has a non-inflatable area 22.

On what might be termed the outer side of the cuff, using the term inthe sense of the side that is exteriorly disposed when the cuff isapplied to the limb, there is provided an aneroid holder 24, in the formof a small, rectangular piece of fabric open at its top and bottom, andstitched to the outer side of the bladder 20 along the opposite sideedges of the holder.

Connecting means is embodied in the cuff, for the purpose of separablyjoining the opposite end portions of the cuff in an overlapped relation,when the cuff is applied to the patients limb. The connecting means inthe illustrated example includes, on the inner face of the cuff, a pad26, located substantially midway between and in parallel relation to theopposite longitudinal edges of the body, and extending almost the fulldistance from the line of stitching 18 to the fold line 14. Pad 26 is injuxtaposition to a label 28, which is also stitched to the area 22 ofthe cuff body, and which is provided at one end with an indicium 30comprising a main size indicator. By this is meant an indication ormarking of the general, overall size of the cuff. As previously noted inthis application, the cuff would likely be made in three mainly usedsizes in a typical commercial embodiment. This would be a size foradults, a size for children, and a size for obese individuals. However,other accepted sizes are also envisioned, as for example sizes forinfants and the newborn, sizes for application to the thigh, etc. In theillustrated example, the adult size, denoted by the indicium A isillustrated by way of an example. Regardless of the size of the cuff, inevery instance it would be provided with other indicia 32, 34, 36,having an important purpose in carrying out the inventive concept,namely, the provision of a visual reference whereby the user mayascertain whether the cuff application is within the limits of assuredaccuracy as regards the taking of a blood pressure recording. Y

The indicia 32, 34, 36 in the illustrated example, but not necessarily,are in the form of lines of stitching beginning on the label, andcontinuing across the pad 26 as shown at 38, 40, 42. These lines ofstitching would be in a conspicuously colored material, as compared tothe color of the pad and the cuff body, so as to be conspicuouslydisplayed to the user of the cuff.

The construction of the pad is of interest. It is intended to cooperatewith a mating pad 44, stitched to the body 19, on the outer surface ofthe body, at the end of the body opposite from the pad 26. Pad 44 andpad 26 are disposed in face to face contact when the cuff is applied tothe arm A, during normal usage of the device, and in thesecircumstances, the pads adhere to one another to maintain closure of thecuff. The pads are separable fastening devices comprising face to facemembers each provided with a very large number of closely spaced,interengagable hooking elements. Thus, the elements on pad 26 may behooks made of flexible, resilient material, while those of pad 44 wouldbe loops also of a flexible, resilient material. These pads are alreadyknown, being fully disclosed in U.S. Pat. No. 3,009,235 and sold underthe trademark Velcro (a trademark of Velcro Corporation, 681 5th Ave,New York, N. Y

For the purposes of the present application, it is sufficient to notethat the pads 26, 44 together constitute cooperating connecting means ofthe opposite end portions of the cuff, which connecting means normallymaintains cuff closure if the cuff is used within the limits of assuredaccuracy, or within a toleranced excess value above said limits. It isfurther sufficient to note that when the cuff is used above thepredetermined, maximum safe limit, the connections will separate whengas pressure is applied to the occluding bladder, preventing use of thecuff beyond the prescribed limits.

in normal use of the cuff, it is wrapped about the arm in the mannershown (FIG. 3), and in the circumstances, pads 26, 44 will be broughtinto face to face contact, and pad 26 will be pressed against the pad 44to adhere thereto and maintain closure of the cuff. It is important tonote that indicium 30 bears the value N, while the indicia 34, 36 bearthe values 10, 20 percent respectively.

The preferred ratio of bladder width to arm diameter is 1.2 to 1, thatis, the width of the bladder (for example, 5 inches) is equal to theapproximate diameter of the arm about which the cuff is wrapped.However, there may be accepted tolerance levels, for example 1 to 1.

It should be noted that the average sphygmomanometer scale is 309 mm.which is considerably higher than most abnormally high blood pressurerecordings.

The procedure in taking blood pressure requires elevating the cuffpressure rapidly to considerably (30-40 mm. Hg.) above the systolicpressure as determined by the palpatory method. The cuff is then slowlydecompressed at a rate of 2 to 3 mm. per heartbeat. Thus, at a bloodpressure recording (by palpatation) of 250 cm. systolic the pressureshould be raised to almost 300 mm. When this occurs on the disclosedcuff at a ratio greater than 1 to l (limb diameter to bladder width) thecuff fails to hold, thus insuring the recorder and those who rely on thewritten recording, with or without knowledge of patient limb size, thatthe cuff used has reasonably conformed to standard medicalrecommendations (i.e. gross error due to cuff sizing cannot occur). Themagnitude of this error with current cuffs, which exceed standardrecommendations by up to 50 percent, may result in errors as high as 60mm.

In other words, during normal use of a blood pressure cuff, the usermust apply the gas pressure rapidly to a value well above the highestblood pressure that would be expected. In accordance with the invention,a relationship is established between the holding power of theconnecting means, and the value of this maximum, normally appliedpressure required for taking a recording.

If the cuff is used within the prescribed ratio, that is, if the limbdiameter is equal to or less than the cuff width, the indicium 32,signifying normal use registers with the edge 46 of pad 44, which edgeis itself an indicium or reference point the location of which is to beobserved in respect to the indicia 32, 34, or 36. If

indicia 32, 46 register, the ratio of the limb diameter to the width ofthe cuff is l to 1. If indicium 46, when the end portions of the cuffare overlapped, is to the left of indicium 32, viewing the same as inFIG. 3, the limb diameter is less than the cuff width and an accuratereading is still assured.

If, however, the limb diameter exceeds the cuff width, it may be thatthe indicium 34 will now register with indicium or marking 46. In thesecircumstances, the user has exceeded the recommended limit of assuredaccuracy, but not to a dangerous extent. The connecting means will thuscontinue to hold.

The connecting means will also hold if the user exceeds the limit ofassured accuracy by 20 percent, that is in circumstances in-which themarking 36 registers with the reference line or marking 46.

Beyond the 20 percent high tolerance, however, the cuff is designed toopen upon inflation to the extent described above when one carries outthe accepted, normal technique of taking a blood pressure recording.This is by reason the fact that, in these circumstances, the entirewidth of pad is not in mating, adhering relationship to the pad 26. Thereduction in the area of connection between the two pads causes the lossof holding power, and under the cuff-opening force resulting from thenormal inflation of the bladder, the loss of holding power is such as tocause the cuff to open, thus incorporating the fail-safe characteristicpreviously described herein.

Thus, the possibility of gross inaccuracies due to improper sizing,which possibility has been noted in other cuffs, is minimized incarrying out the present invention. intentional or inadvertent disregardof the safe limits of assured accuracy as set forth in the illustratedexample, is obviated.

it is also to be noted that the selection of the location of theindicia, in relation to the dimensions of the bladder width and thelocation and form of the connecting means, is such as to cause the cuffto embody standards acceptable both to the American Heart Associationand the World Health Organization schools of thought, and has apractical effect of resolving differences between these schools asacademic. In other words, the indicia are selected and located, inreference to the connecting means, such as to satisfy all recognized,known scientific authority heretofore speaking on the establishment ofstandards as to cuff width in relation to limb diameter. One need onlyapply the cuff as described above, after selecting the proper main size,to assure the taking of an accurate reading, without regard to theparticular school of thought favored by the user.

A further discussion of the capability of the invention to resolvedifferences between the American Heart Asgests that a 14 cm. Width X 42cm. length cuff obviates the need for concern on the width of a bloodpressure cuff, since the cuff (bladder) completely encircles the arm. inother words,- one school of thought holds that width is the key factorif the l to 1.2 ratio is held, while the other school of thought holdsthat the length is the key factor, provided the width is 14 cm. Inessence, my cuff resolves this difference by marking at the l to 1.2ratio which in turn gives 75 percent encirclement (on adult, 100 percenton other sizes). Other sizes are then provided which conform to completeencirclement.

I claim:

1. A blood pressure cuff comprising:

a flexible, elongated body having end portions overlapping in anoperative, limb encircling disposition, said body having an occludingbladder, connectable to a source of fluid under pressure;

holding means for releasably connecting the overlapping end portions ofsaid elongated body;

said holding means having a predetermined holding force, related to theratio of limb diameter to the width of said bladder; and

said holding means being operable to release said overlapping endportions in response to the application of a separating force, duringthe operative application of said cuff, which separating force is inexcess of said predetermined holding force.

2. A blood pressure cuff according to claim 1, wherein said holdingmeans comprises mating connecting elements on said end portions; and

said connecting elements have a holding force which decreases to theextent of reduction of the area of overlap of the end portions.

3. A blood pressure cuff as in claim 2, wherein said connecting elementscomprise an area of hook members on one end portion in face-to-facecontact with and separably interengaging an area of loop members on theother end portion.

4. A blood pressure cuff as in claim 3 in which said areas areincreasingly offset from one another and hence have progressively lesscontact with each other, in proportion to a progressively greaterreduction in the extent of overlap of said end portions.

5. A blood pressure cuff comprising:

a. a flexible, elongated body having end portions 8 overlapping in anoperative, limb encircling position of the body, said body having anoccluding bladder connectable to a source of fluid under pressure;

- b. means on the body utilizing the ratio of limb diameter to the widthof the occluding bladder,-to indicate a limit of assured accuracy in therecording of ones blood pressure; and

c. separable connecting means on the respective end portions releasablyholding the same together in the limb-encircling position of said body.

6. A blood pressure cuff as in claim 5 wherein said first-named meanscomprises indicia on at least one of said end portions indicating theextent of overlap of the end portions in terms of the extent ofdeviation, if any, from a predetermined norm.

7. A blood pressure cuff as in claim 6 wherein said indicia are spacedlongitudinally of said one end portion.

8. A blood pressure cuff as in claim 7 wherein an indicium is providedon the other end portion, whereby the extent, if any, of deviation fromsaid norm is determined by visual observation of the angular position ofsaid indicium in respect to any of the indicia of said one en ortionithe limb-en 'rcli ition oft ebod A pressure cuii as iii l im 8, saisecon named means being operative to lose holding power with resultantopening of the cuff in response to the normal application of pressurefluid to the bladder under conditions in which the ratio of limbdiameter to the bladder width is in excess of a predetennined value, andin which said ratio is visibly shown to be in excess of said value byreference to the relative displacement of the indicia of the respectiveend portions.

10. A blood pressure cuff as in claim 9 wherein said second-named meanscomprises strips of hook members and loops on the respective endportions, separably interengaging to hold the end portions together,said indicia extending across at least one of said strips as a visualreference of the extent to which said strips may be angularly displacedwithout a critical loss of the holding power thereof.

1. A blood pressure cuff comprising: a flexible, elongated body havingend portions overlapping in an operative, limb encircling disposition,said body having an occluding bladder, connectable to a source of fluidunder pressure; holding means for releasably connecting the overlappingend portions of said elongated body; said holding means having apredetermined holding force, related to the ratio of limb diameter tothe width of said bladder; and said holding means being operable torelease said overlapping end portions in response to the application ofa separating force, during the operative application of said cuff, whichseparating force is in excess of said predetermined holding force.
 2. Ablood pressure cuff according to claim 1, wherein said holding meanscomprises mating connecting elements on said end portions; and saidconnecting elements have a holding force which decreases to the extentof reduction of the area of overlap of the end portions.
 3. A bloodpressure cuff as in claim 2, wherein said connecting elements comprisean area of hook members on one end portion in face-to-face contact withand separably interengaging an area of loop members on the other endportion.
 4. A blood pressure cuff as in claim 3 in which said areas areincreasingly offset from one another and hence have progressively lesscontact with each other, in proportion to a progressively greaterreduction in the extent of overlap of said end portions.
 5. A bloodpressure cuff comprising: a. a flexible, elongated body having endportions overlapping in an operative, limb encircling position of thebody, said body having an occluding bladder connectable to a source offluid under pressure; b. means on the body utilizing the ratio of limbdiameter to the width of the occluding bladder, to indicate a limit ofassured accuracy in the recording of one''s blood pressure; and c.separable connecting means on the respective end portions releasablyholding the same together in the limb-encirCling position of said body.6. A blood pressure cuff as in claim 5 wherein said first-named meanscomprises indicia on at least one of said end portions indicating theextent of overlap of the end portions in terms of the extent ofdeviation, if any, from a predetermined norm.
 7. A blood pressure cuffas in claim 6 wherein said indicia are spaced longitudinally of said oneend portion.
 8. A blood pressure cuff as in claim 7 wherein an indiciumis provided on the other end portion, whereby the extent, if any, ofdeviation from said norm is determined by visual observation of theangular position of said indicium in respect to any of the indicia ofsaid one end portion in the limb-encircling position of the body.
 9. Ablood pressure cuff as in claim 8, said second-named means beingoperative to lose holding power with resultant opening of the cuff inresponse to the normal application of pressure fluid to the bladderunder conditions in which the ratio of limb diameter to the bladderwidth is in excess of a predetermined value, and in which said ratio isvisibly shown to be in excess of said value by reference to the relativedisplacement of the indicia of the respective end portions.
 10. A bloodpressure cuff as in claim 9 wherein said second-named means comprisesstrips of hook members and loops on the respective end portions,separably interengaging to hold the end portions together, said indiciaextending across at least one of said strips as a visual reference ofthe extent to which said strips may be angularly displaced without acritical loss of the holding power thereof.